Winter Storm Warning 3, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
420 AM CDT FRI MAR 27 2009

.DISCUSSION...
THE PREVIOUS WINTER STORM WARNING WILL BE UPGRADED TO A BLIZZARD
WARNING AND THE PREVIOUS WATCH WILL BE EXPANDED AND CONVERTED TO A
WINTER STORM WARNING. BLIZZARD CRITERIA WILL LIKELY BE MET BUT NOT
FOR THE ENTIRE WARNING PERIOD. GIVEN VERY SIGNIFICANT SNOW
ACCUMULATIONS AND BLOWING/DRIFTING EXPECTED...THE HARDER BLIZZARD
WARNING SHOULD GET RIGHT MESSAGE ACROSS TO THOSE ACROSS NORTHWEST
PARTS OF THE STATE AND IT WILL BLEND WELL WITH SURROUND WFO
HIGHLIGHTS. A FEW COUNTIES WERE ADDED FOR THE NEW WARNING. THIS
WILL INCORPORATE AREAS FROM LAWTON...UP THROUGH CHICKASHA...
NORMAN...AND SHAWNEE. GOING TO BE A TIGHT GRADIENT ON SOUTHERN
END OF HEAVIER ACCUMULATIONS...SO IT IS POSSIBLE THAT THE SOUTHERN
PORTIONS OF THE MOST SOUTHERN COUNTIES IN THE WARNING MAY NOT GET
MUCH SNOW. ADVISORIES CANNOT BE RULED OUT LATER TODAY JUST SOUTH
OF NEW WARNING...SOMETHING THAT THE DAY SHIFT WILL MONITOR AND
TAKE ACTION IF NEEDED. AS FAR AS TIMING...WE WILL START THE NEW
WARNING A LITTLE LATER...THIS EVENING THROUGH TOMORROW...ROUGHLY
FROM THE I-35 CORRIDOR EAST AND NORTHEAST. CHANGE OVER IN THE
OKLAHOMA CITY METRO AREA WILL LIKELY WAIT UNTIL MID-LATE AFTERNOON
WITH ACCUMULATIONS NOT EXPECTED UNTIL THIS EVENING. THIS BEING
TYPED WITH THE CAVEAT THAT WITH INTENSIFYING SYSTEMS SUCH AS
THIS...THE COLD AIR CAN SURGE FARTHER AND FASTER THAN PROGD.
STILL...A CHANGE OVER IN THE 4 TO 7 PM TIME-FRAME STILL LOOKS
CAUTIOUSLY REASONABLE.

MODEL DERIVED SNOWFALL TOTALS STILL OFF OF THE CHARTS (25 TO 30
INCHES ACROSS NORTHWEST 1/4 OF OKLAHOMA). WE INCREASED THEM A BIT ON
SOUTHERN FRINGE OF WARNING AND ACROSS NORTHWEST OKLAHOMA BASED ON
LATEST SREF...HPC COORD...AND OTHER WFO GRIDDED FORECASTS.
DEFORMATION/PIVOT POINT OF MID-LEVEL FLOW WILL ALLOW FOR A BAND OF
WELL OVER A FOOT SOMEWHERE...CURRENTLY MOST LIKELY ACROSS
NORTHWEST OKLAHOMA UP INTO SOUTH-CENTRAL KANSAS.

REST OF PACKAGE...SUNDAY AND BEYOND...WAS DERIVED FROM GFS
INITIALIZATIONS WITH VERY LITTLE MODIFICATIONS.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  46  30  39  26 /  90 100  60   0
HOBART OK         39  28  40  28 /  90  90  30   0
WICHITA FALLS TX  50  31  46  33 /  60  50  10   0
GAGE OK           31  22  36  22 / 100 100  30   0
PONCA CITY OK     39  30  36  21 / 100 100  80   0
DURANT OK         60  34  46  35 /  70  50  30   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM CDT SATURDAY
     FOR OKZ008-013-019-020-025-026-028>030.

     WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO 1 PM CDT
     SATURDAY FOR OKZ018-022>024-027-033>036-038.

     BLIZZARD WARNING FROM 7 AM THIS MORNING TO 1 PM CDT SATURDAY FOR
     OKZ004>007-009>012-014>017-021.

TX...WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO 1 PM CDT
     SATURDAY FOR TXZ083.

&&

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HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
1131 PM CDT THU MAR 26 2009

OKZ004>048-050>052-TXZ083>090-271300-
HARPER-WOODS-ALFALFA-GRANT-KAY-ELLIS-WOODWARD-MAJOR-GARFIELD-NOBLE-
ROGER MILLS-DEWEY-CUSTER-BLAINE-KINGFISHER-LOGAN-PAYNE-BECKHAM-
WASHITA-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN-CLEVELAND-
POTTAWATOMIE-SEMINOLE-HUGHES-HARMON-GREER-KIOWA-JACKSON-TILLMAN-
COMANCHE-STEPHENS-GARVIN-MURRAY-PONTOTOC-COAL-COTTON-JEFFERSON-
CARTER-JOHNSTON-ATOKA-LOVE-MARSHALL-BRYAN-HARDEMAN-FOARD-WILBARGER-
WICHITA-KNOX-BAYLOR-ARCHER-CLAY-
1131 PM CDT THU MAR 26 2009

THIS HAZARDOUS WEATHER OUTLOOK COVERS NORTHERN...WESTERN...
CENTRAL...AND SOUTHERN OKLAHOMA...AND WESTERN NORTH TEXAS.

.DAY ONE...TONIGHT...

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVERNIGHT ACROSS
PORTIONS OF OKLAHOMA.

LOCATION...
THE SLIGHT RISK AREA IS SOUTH AND EAST OF A CHANDLER... TO EL RENO
AND DUNCAN OKLAHOMA LINE.

TIMING...
THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS WILL BE THROUGH 3 AM.

IMPACTS...
MAIN RISKS WILL BE HAIL UP TO THE SIZE OF QUARTERS AND WIND GUSTS TO
60 MPH.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS THROUGH
3 AM.

DISCUSSION...
A WARM FRONT WILL MOVE NORTH AND STALL NEAR THE RED RIVER. A
MID-LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION OVERNIGHT. A LOW
LEVEL JET WILL ALSO DEVELOP. THE LIFT ASSOCIATED WITH THE LOW LEVEL
JET AND DISTURBANCE MAY BE ENOUGH FOR ADDITIONAL SHOWERS AND
THUNDERSTORMS TO DEVELOP IN PORTIONS OF CENTRAL AND SOUTHERN
OKLAHOMA OVERNIGHT. IN ADDITION... THE APPROACH OF AN UPPER-LEVEL
STORM WILL SUFFICIENTLY COOL THE MID LEVELS OF THE ATMOSPHERE. IF
STORMS DEVELOP... A FEW SEVERE STORMS MAY BE POSSIBLE WITH LARGE
HAIL THE PRIMARY CONCERN.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT FRIDAY MAR 27.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...60 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...20 PERCENT.

OTHER HAZARDOUS WEATHER...
RAIN MAY BEGIN TO CHANGE TO SNOW EARLY FRIDAY MORNING IN PORTIONS OF
NORTHWEST OKLAHOMA.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY...

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS FRIDAY MORNING IN
SOUTHEAST OKLAHOMA.

OTHER HAZARDOUS WEATHER...
A DEVELOPING MAJOR STORM IS EXPECTED TO CAUSE ACCUMULATING SNOW OVER
NORTHERN AND WESTERN OKLAHOMA FRIDAY AND FRIDAY NIGHT. SNOW ALSO MAY
ACCUMULATE IN PARTS OF CENTRAL OKLAHOMA AND WESTERN NORTH TEXAS
FRIDAY NIGHT AND SATURDAY. HEAVY SNOW WILL BE POSSIBLE IN NORTHERN
AND WESTERN OKLAHOMA. STRONG NORTH WINDS WILL BE LIKELY CAUSING
CONSIDERABLE BLOWING AND DRIFTING SNOW. ACROSS PORTIONS OF NORTHERN
AND NORTHWESTERN OKLAHOMA A WINTER STORM WARNING IS EFFECTIVE FROM 7
AM FRIDAY THROUGH MID-DAY SATURDAY. A WATCH IS IN EFFECT FARTHER
SOUTH ACROSS PORTIONS OF CENTRAL INTO SOUTHWEST OKLAHOMA AND A SMALL
PART OF WESTERN NORTH TEXAS FOR THE SAME TIME PERIOD.

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